This invention relates to an acceleration responsive device. More particularly, this invention relates to a device which, when moved by a user, will register an indication of the acceleration effected during movement of the device.
In the sport of golf, many different structural types of golf clubs are available for a golfer. Each golfer possesses certain physical abilities which are unique to that golfer and, to some extent, are different from other golfers. To accommodate these differences amongst golfers, and to balance these differences amongst the players in the competitiveness of playing golf, golf clubs are manufactured, for example, with different shapes and weights of club heads. In addition, to further accommodate these differences, club shafts are available with different stiffnesses or flexibility.
It is believed that a golfer can enhance the results of the golfer's game by selecting clubs having a shaft stiffness which is most suited for the golfer's particular physical ability to play the game. While this may not insure that the golfer will be a top performer, it does provide the appropriate equipment for the golfer to play the game within the golfer's abilities with less of a concern for having to compensate, during play, for ineffective equipment. This tends to put the pleasure and enjoyment of playing the game, and the competitiveness with other players, at the level of each golfer's abilities rather than a measure of the differences in the quality of the properties of the clubs used by each golfer.
While recognizing that stiffness of the shaft of a golf club is an important factor in a golfer's personalized selection of the equipment to be used, there is a disparity in theories regarding the physical principles to be considered when making such selection. In some instances, it has been the belief that the velocity of the golfer's swing of the club is a major factor to be considered when selecting the stiffness of the club most suited for the golfer. Based on the velocity premise, there is a tendency for some golfers to select shafts which are too stiff. Further, in some cases, the velocity of the club head at the point of impact with the ball can be misleading with respect to club acceleration or "load up" conditions during the downswing. This can lead to an inappropriate selection of shaft stiffness.
It has been determined that the primary structural consideration in selecting the appropriate shaft stiffness for a particular golfer is the amount of "load up" or acceleration applied to the club during the swing, and not the velocity. It has been shown that, as a general rule, the greater the club acceleration ("load up") the greater the golfer's need for a stiffer shaft.
To optimize club/biomechanical performance, the golfer must use a club flex that provides the maximum feedback (flexural deflection) the golfer can control. Since control is related to athletic ability, it is very difficult to define in an engineering sense. Nevertheless, it has been determined that the more acceleration applied to the club during the downswing, the greater the stiffness the average golfer requires to obtain good position repeatability at impact with the ball.
While the foregoing remarks have been made with respect to a golfer regarding the acceleration premise of personalized selection of the shaft stiffness of golf clubs, the principal stated above could be applied to any moving object such as, for example, baseball bats, tennis rackets and the like where the acceleration consideration is significant.
Thus, in view of the importance of the acceleration-related data as noted above, there is a need for a device which will readily provide an indication of the acceleration attained in the moving of the device by an individual who is moving the device. There is also a need to provide methods of using the obtained indications of acceleration to derive critical information leading the individual in the personalized selection of a product which corresponds to the device such as, for example, a golf club.